Final Answer:
The letters CCR stand for "Carbon Copy Receipt" (A).
Step-by-step explanation:
CCR, or Carbon Copy Receipt, is a term originating from the practice of using carbon paper in typewriters to create duplicate copies of documents. In the context of business and communication, CCR denotes a copy of a document that is distributed to someone other than the primary recipient, providing additional parties with information. While carbon paper is less commonly used today due to digital advancements, the term "CC" or "Carbon Copy" has persisted in email culture, signifying the inclusion of additional recipients in an email message to keep them informed.
Understanding the acronym CCR is essential in historical contexts and for those familiar with traditional office practices involving the use of carbon paper for document duplication.